Symptoms come and go?

Sarah
I'm only 5 weeks just today but I felt pretty nauseous last week. Especially last night I felt like crap. Today I don't feel any symptoms at all so I'm worried my hcg is dropping. This of course is after getting a good blood draw last night. My hcg is 553 and my doctor thinks it should be higher. I'll get another one tomorrow but is this normal?!